The present application is directed to a fly capable clamp assembly for testing magnetic recording of a substrate, and a method of making and using the same. The present method permits mechanical fly and magnetic testing of magnetic sliders used in the hard disk drive industry. This invention relates to a slider supporting apparatus for flying a slider of a hard disk drive in the manufacturing process to provide electrical performance characteristics.
A disk drive head gimbal assembly (HGA) with a magnetic head is used to write and read data to and from a disk drive. Conventional magnetic heads (also referred to as sliders) are mounted on suspensions as they are tested for read/write performance during the manufacturing process by enabling the tester to fly the slider, set the head media spacing and test for magnetic performance of writer and reader elements. A slider tester is used to characterize the performance of the HGA. The sliders which are found to be non-defective as a result of the checks are incorporated into the disk drive manufacturing. The sliders found non-functional are rejected. The rejected sliders may require either disposing of the non-functional HGAs or reworking by removing the sliders and recycling the suspensions. The slider removal/reworking operation causes suspension damage, as well as pitch and roll static deformation.
Accordingly, slider testers have been developed that can inspect each individual slider. In a conventional slider tester described in U.S. Pat. No. 6,943,971 B2, depicted in FIG. 1, sliders are supported so as to mimic the suspension. A recording medium such as a magnetic disk is rotated to provide an air bearing surface to the slider to provide the proper head media spacing so as to perform write and read operations. A tester for measuring the performance of the slider without permanent assembly of the slider to the suspension is advantageous in cost. The tester is capable of simulating approximate conditions of the slider. However, with the advent of dynamic fly height adjust, a contact detection operation is performed to set the proper clearance between the magnetic medium and the write and read sensors.
Consequently, slider supporting apparatuses have been developed that have a load beam and flexure constructed in the same manner as those of actual suspensions, which can be removably fitted with a slider. One such slider supporting apparatus is described in US 2006/0236527 A1 and 2007/0263325 A1. FIGS. 2 and 3 depict a head gimbal assembly for removably testing sliders. As shown in FIG. 2, this conventional slider supporting apparatus includes a portion including a tongue, a pair of bellows portions functioning as springs, a first support portion, and a second portion, etc., which constitute a part of the flexure. Each bellows portion has a top and bottom that are formed by plastic deformation. This formation may be achieved by corrugating a part of the flexure in its thickness direction like waves. The slider is placed on the tongue with the bellows portions stretched in the direction of arrow T by means of a jig not shown. Thereafter, the bellows are released from the applied tension, whereupon the slider is clamped between the bellows springs and the support. To increase the stroke of the bellows structure, the number of bellows may be increased. The length of the spring structure cannot be increased and is limited by the size of the slider structure. The bellows apply an undesirable out of plane moment tending to pop the slider out of the tongue due to manufacturing tolerances during the plastic forming of the bellows. The moment can also contribute to generating pitch and roll static torque contributing to load and unload magnetic media damage and slider media contact during the slider testing.
FIG. 3, from US Patent Publication No. 2006/0236527 A1 shows a portion of the load beam formed to provide a rigid tab perpendicular to a support at the leading edge of the slider. A second forming operation of a flexible tab at the trailing edge on the support is performed. The flexible tab deforms to provide an opening for inserting the slider into the tongue formed into the support. The flexible tab produces a holding force to secure the slider during the loading and unloading onto the magnetic media. The rigid tab can be configured to provide an electrical interconnection between the slider and the electrical interconnect. The embodiment of FIG. 3 suffers from the same problems noted above with regard to FIG. 2.
Another proposed solution from U.S. Pat. No. 6,943,971 B2 shown in FIG. 4 provides a slider supporting apparatus provided with a flexure formed of a metal plate having spring characteristics, the flexure includes a portion having a first tongue, a second support portion including a second tongue for supporting the slider. The spring portion is composed of a pair of flat springs each including a plurality of alternate convexes and concaves formed along the side of the first tongue and configured to extend to a length which allows the slider to be inserted between the first and second support portions when subjected to a tensile load. This zigzag design offers the benefit of increasing the stroke of the spring while limiting permanent deformations. The alternating concaves and convexes provide a low out of plane stiffness and a large exposed real estate area susceptible to windage excitation during the loading onto a rotating magnetic medium during slider tester. Windage excitations cause out of plane excitations imparted to the slider during write read operation leading to off track motions. This design presents limitations in increasing the frequency response of the system leading to a reduction in the number of zigzags which in turns limits the stroke of the design.
A slider suspension assembly for a slider tester is provided which includes another mechanism from U.S. Pat. No. 6,459,260 as shown in FIG. 5. The assembly includes an electrical interconnect, such as a flex circuit. The socket is adapted to secure a slider and electrically couple the interconnect to the slider. The socket includes elements tightly spaced to secure the slider in the socket opening. A clamp bar is urged against slider with the assistance of beam springs that extend longitudinally with respect to slider. After the slider is placed between the clamp bar and interconnects, the slider is firmly supported. Longitudinal springs attached to the clamp bar urge the slider to be biased against the electrical contacts. A large number of beam springs are adapted to increase the load applied to secure the slider in place. Minimizing the stress at the beams has lead to designing long tapered beams at the leading and trailing edge of the slider resulting in a substantially large design that adds excessive mass at the suspension end. This mass increase reduces the frequency response of the head assembly and induces an increase of load/unload contact probability, which in turn causes frequency response deterioration.
It is within this context that the present embodiments arise.